The present invention relates to methods for producing chewing gums. In particular, the invention relates to a method for continuous chewing gum production using extrusion apparatus.
The batch method of producing chewing gums has long been considered the standard for producing chewing gums on a commercial scale. Such methods, however, tend to be labor intensive and produce chewing gums of varying consistency. The batch process typically requires using large kettles for the extensive mixing and kneading of a gum base and plasticizers into a viscous melt. Thereafter, softeners and bulking agents such as sugars or sugar alcohols are added to the molten mass with stirring. Later, flavorings, such as flavor oils and/or spray-dried flavors, and sweeteners are added while mixing is continued until a homogenous mass is achieved. The chewing gum mass is thereafter cooled and then later rolled, scored and wrapped into the final product. The above described method often required multiple mixing steps and transferral of the gum mass from various production apparatus and work areas until the final product was completed. Further, since the batch process was unmechanized, the various mixing and kneading steps required the continuous input of the chewing gum artisan to determine when ingredients were to be added to the batch. Since the timing of the ingredient additions to the molten mass was subjectively based, the final products often varied in texture and/or flavor from batch to batch.
Over the years, various attempts by the industry to replace the batch process for the bulk manufacture of chewing gums have been made. U.S. Pat. Nos. 1,852,005 and 1,953,295 disclose early continuous production methods and apparatus for producing chewing gum strips. These initial attempts, however, had several shortcomings. For example, these patents disclose methods using a single entry port for the ingredients and subjecting all of the ingredients to plasticizing temperatures throughout an extrusion process before allowing a gum slab to exit. While providing continuous output of a chewing gum slab, these methods proved to be unacceptable. Continuous heating of the gum ingredients and the single entry port caused opportunities for delicate ingredients such as flavor oils to "flash off" or degrade due to the prolonged exposure to high temperatures and considerable pressure throughout the extrusion process.
U.S. Pat. No. 3,455,755 discloses a method and apparatus for continuously casting slabs of chewing gums and for accordion-like pleating and stacking of the slab. This method, like the earlier methods described, suffers from using a single entry port for introducing the gum ingredients. The extended period of heat exposure and pressure build-up which can detract from the organoleptic qualities of the resulting gum remained. In addition, the cooling of the chewing gum slabs is accomplished by depositing the molten chewing gum material on a conveyer belt maintained under water for the greater part of its length. The ability to precisely locate crucial points for the addition of temperature sensitive materials such as flavor oils is not disclosed. U.S. Pat. No. 3,644,169 has a similar disclosure.
More recently, U.S. Pat. No. 4,555,407 discloses a method for continuously forming wide, thin chewing gum slabs using a twin screw extruder. According to this method, a chewing gum paste is formed by continuously introducing into a first feed port of an extruder pelletized gum base, corn syrup, a portion of granulated sugar, plasticizer and coloring ingredients. The remaining sugar is then continuously introduced into a second port just past the first feed port. Flavoring ingredients are not added until at least about three-quarters of the length of the extruder from the feed end to minimize the amount of time the flavoring ingredients are exposed to the heat of the extruder. After exiting from the extruder through a coat hanger-type die, the gum paste slab is quickly cooled before being passed through calendar rolls to adjust the thickness of the gum paste slab. Thus, while providing for selective and timed addition of some ingredients, the extensive cooling of the gum paste slab remained outside of the extruder as shown in prior art methods. Such cooling, however, can be uneven and variations in the cooling rate are known to result in adverse textural qualities of the final product.
Accordingly, none of the related art describes a method for the continuous preparation of a chewing gum slab from chewing gum ingredients in the absence of requiring a separate cooling step. A need, therefore, exists for a method of continuously producing chewing gum slabs which do not require a separate cooling step once the slab has exited from the extruder.
It is, therefore, an object of the present invention to provide an improved method for the continuous preparation of chewing gum slabs for producing a chewing gum product in the absence of requiring a separate cooling step after the gum slab has exited the extruder. Other objects will be apparent from the disclosure set forth herein.